Conventionally, in general, a lawn mower comprises a mower device having a rotary mowing blade and attached to a traveling body to be lifted up and down, a discharge duct having a tubular shape and extending backward from the mower device, and a box-shaped grass collector communicating with the discharge duct, wherein the lawn mower continuously mows grass, etc. on the ground with the mower device, and the mowed grass such as the lawn grass is discharged to the grass collector through the discharge duct from the mower device.
In this case, the conventional lawn mowers have employed an arrangement, wherein the grass collector are supported at both sides thereof by right and left booms provided on a traveling body, when the grass collector becomes full of mowed grass, the grass collector is lifted above a container or a loading space of a truck, etc. by raising distal ends of the right and left booms with proximal ends thereof as fulcrums, and the mowed grass in the grass collector is discharged into the container or the loading space of the truck, etc. (for example, see Patent Document 1). Also, well-known to the person skilled in the art is an arrangement wherein right and left fixed masts are erected on a rear part of a running vehicle, and a grass collector is supported to the fixed masts to be lifted up and down, and the mowed grass in the grass collector is discharged into the container, etc. (for example, see Patent Document 2 or 3).    [Patent Document 1] JP 2002-84850 A    [Patent Document 2] JP 09-9759 A    [Patent Document 3] JP 09-47134 A